The present invention relates to an assembly and method for installing sliders and end terminations onto a zipper for plastic bags.
Reclosable plastic bags are used for storage of food and a variety of other items. These bags include an open mouth for filling the bag. A reclosable zipper is secured to the mouth for closing the mouth when desired. One form of reclosable zipper used is a pinch to close, pull to open zipper. Another form of reclosable zipper includes a slider that is moved along the zipper between end termination clips to open and close the zipper. An example of this bag and zipper is disclosed in U.S. Pat. No. 5,067,208.
In the manufacture of reclosable plastic bags that are opened and closed using a slider, it is desirable to install the slider onto the zipper as fast as possible so as not to slow down the speed of the bag making machinery. Several methods of inserting sliders onto a fastener using a rotary process have been proposed. Examples can be found in U.S. Pat. Nos. 6,161,271 and 6,199,256 B1 and United Kingdom Patent Application No. 2,085,519 A.
These proposed processes, however, do not insert end termination clips onto the zipper and a separate machine is required to insert end clips. These additional machines increase the cost of making bags and reduce the speed at which the bags can be made. It is desirable to provide an assembly and method for simultaneously installing a slider and end termination clips onto a zipper without slowing down the bag making process and without unduly increasing the cost of making bags.
The present invention is directed to an assembly and method for installing sliders and end terminations onto reclosable zippers for plastic bags.
The assembly for installing sliders and end terminations onto a zipper includes a base having a cam path. A rotor is mounted on the base and includes a cam follower that fits into the cam path. At least one slider installation member and one end termination installation member are mounted on the rotor one of which is rigidly secured to the rotor and the other is reciprocally mounted on the rotor. The cam follower is connected to the slider installation member or end termination installation member that is reciprocally mounted on the rotor and reciprocates this nest as the cam follower moves in the cam path. A motor rotates the rotor moving the slider installation member to an assembly of sliders and a slider is inserted into the slider installation member. Simultaneously, the end termination installation member is moved to a supply of end terminations and end terminations are inserted into the end termination installation member.
The slider installation member and end termination installation member are then rotated to a position adjacent to a zipper and the slider and end termination are simultaneously mounted onto a zipper on a web of bag film. The zipper and web are then cut between adjacent end terminations to form separate bags each with a slider and an end termination clip on the zipper. This method of installing sliders and end terminations onto a zipper does not slow down the bag making operation and requires only a single insertion machine.